megan gimple / SDFileSystem

Important changes to repositories hosted on mbed.com

Mbed hosted mercurial repositories are deprecated and are due to be permanently deleted in July 2026.

To keep a copy of this software download the repository Zip archive or clone locally using Mercurial.

It is also possible to export all your personal repositories from the account settings page.

Dependents:   gimple_A4_3_Temp_Light

FATFileSystem/MemFileSystem.h@0:07ff9ae5339f, 2021-11-13 (annotated)

Committer:
mgimple
Date:
Sat Nov 13 20:10:05 2021 +0000
Revision:
0:07ff9ae5339f
SD

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mgimple 0:07ff9ae5339f 1 /* mbed Microcontroller Library - MemFileSystem
mgimple 0:07ff9ae5339f 2 * Copyright (c) 2008, sford
mgimple 0:07ff9ae5339f 3 */
mgimple 0:07ff9ae5339f 4
mgimple 0:07ff9ae5339f 5
mgimple 0:07ff9ae5339f 6 #ifndef MBED_MEMFILESYSTEM_H
mgimple 0:07ff9ae5339f 7 #define MBED_MEMFILESYSTEM_H
mgimple 0:07ff9ae5339f 8
mgimple 0:07ff9ae5339f 9 #include "FATFileSystem.h"
mgimple 0:07ff9ae5339f 10
mgimple 0:07ff9ae5339f 11 namespace mbed
mgimple 0:07ff9ae5339f 12 {
mgimple 0:07ff9ae5339f 13
mgimple 0:07ff9ae5339f 14 class MemFileSystem : public FATFileSystem
mgimple 0:07ff9ae5339f 15 {
mgimple 0:07ff9ae5339f 16 public:
mgimple 0:07ff9ae5339f 17
mgimple 0:07ff9ae5339f 18 // 2000 sectors, each 512 bytes (malloced as required)
mgimple 0:07ff9ae5339f 19 char *sectors[2000];
mgimple 0:07ff9ae5339f 20
mgimple 0:07ff9ae5339f 21 MemFileSystem(const char* name) : FATFileSystem(name) {
mgimple 0:07ff9ae5339f 22 memset(sectors, 0, sizeof(sectors));
mgimple 0:07ff9ae5339f 23 }
mgimple 0:07ff9ae5339f 24
mgimple 0:07ff9ae5339f 25 virtual ~MemFileSystem() {
mgimple 0:07ff9ae5339f 26 for(int i = 0; i < 2000; i++) {
mgimple 0:07ff9ae5339f 27 if(sectors[i]) {
mgimple 0:07ff9ae5339f 28 free(sectors[i]);
mgimple 0:07ff9ae5339f 29 }
mgimple 0:07ff9ae5339f 30 }
mgimple 0:07ff9ae5339f 31 }
mgimple 0:07ff9ae5339f 32
mgimple 0:07ff9ae5339f 33 // read a sector in to the buffer, return 0 if ok
mgimple 0:07ff9ae5339f 34 virtual int disk_read(char *buffer, int sector) {
mgimple 0:07ff9ae5339f 35 if(sectors[sector] == 0) {
mgimple 0:07ff9ae5339f 36 // nothing allocated means sector is empty
mgimple 0:07ff9ae5339f 37 memset(buffer, 0, 512);
mgimple 0:07ff9ae5339f 38 } else {
mgimple 0:07ff9ae5339f 39 memcpy(buffer, sectors[sector], 512);
mgimple 0:07ff9ae5339f 40 }
mgimple 0:07ff9ae5339f 41 return 0;
mgimple 0:07ff9ae5339f 42 }
mgimple 0:07ff9ae5339f 43
mgimple 0:07ff9ae5339f 44 // write a sector from the buffer, return 0 if ok
mgimple 0:07ff9ae5339f 45 virtual int disk_write(const char *buffer, int sector) {
mgimple 0:07ff9ae5339f 46 // if buffer is zero deallocate sector
mgimple 0:07ff9ae5339f 47 char zero[512];
mgimple 0:07ff9ae5339f 48 memset(zero, 0, 512);
mgimple 0:07ff9ae5339f 49 if(memcmp(zero, buffer, 512)==0) {
mgimple 0:07ff9ae5339f 50 if(sectors[sector] != 0) {
mgimple 0:07ff9ae5339f 51 free(sectors[sector]);
mgimple 0:07ff9ae5339f 52 sectors[sector] = 0;
mgimple 0:07ff9ae5339f 53 }
mgimple 0:07ff9ae5339f 54 return 0;
mgimple 0:07ff9ae5339f 55 }
mgimple 0:07ff9ae5339f 56 // else allocate a sector if needed, and write
mgimple 0:07ff9ae5339f 57 if(sectors[sector] == 0) {
mgimple 0:07ff9ae5339f 58 char *sec = (char*)malloc(512);
mgimple 0:07ff9ae5339f 59 if(sec==0) {
mgimple 0:07ff9ae5339f 60 return 1; // out of memory
mgimple 0:07ff9ae5339f 61 }
mgimple 0:07ff9ae5339f 62 sectors[sector] = sec;
mgimple 0:07ff9ae5339f 63 }
mgimple 0:07ff9ae5339f 64 memcpy(sectors[sector], buffer, 512);
mgimple 0:07ff9ae5339f 65 return 0;
mgimple 0:07ff9ae5339f 66 }
mgimple 0:07ff9ae5339f 67
mgimple 0:07ff9ae5339f 68 // return the number of sectors
mgimple 0:07ff9ae5339f 69 virtual int disk_sectors() {
mgimple 0:07ff9ae5339f 70 return sizeof(sectors)/sizeof(sectors[0]);
mgimple 0:07ff9ae5339f 71 }
mgimple 0:07ff9ae5339f 72
mgimple 0:07ff9ae5339f 73 };
mgimple 0:07ff9ae5339f 74
mgimple 0:07ff9ae5339f 75 }
mgimple 0:07ff9ae5339f 76
mgimple 0:07ff9ae5339f 77 #endif